This section provides background information related to the present disclosure which is not necessarily prior art.
It is known to connect thermostats to wireless transceivers for receiving and transmitting information to and from remote devices. Known thermostats with wireless transceivers may be powered via continuous or essentially continuous power. Such continuous power is typically from a common or neutral connector (often referred to as a C connection or wire) or from power stealing. Power stealing is a known technique where power for the thermostat is drawn from or “stolen” from the connections to the heating transformer or the cooling transformer, when such transformers are not connected to a load. Power stealing essentially derives power from a transformer at a current level low enough to prevent the load from being engaged. In such continuous power systems, there is always or almost always sufficient power available that a wireless transceiver is continuously enabled or powered to continuously communicate with remote devices and respond to commands from those remote devices.
It is also known for thermostats that draw power from power sources external to the thermostat to include a power supply internal to the thermostat, such as batteries, when external power is not available. The battery supply may also include additional power backup, such as a capacitor, to maintain power when both the external and internal power are unavailable. In such thermostats, it is also known to provide for reduction of energy consumption when the thermostat relies solely on a battery supply and to provide the user with a notice that the battery energy level is low. These thermostats, however, typically become fully operative when a user engages a user interface (e.g., touch screen, switch, button, etc.) and thus, the thermostat effectively is always available to the user to control heating and cooling. If an internally powered thermostat with a wireless transceiver is to always be available to a user, the internal power supply life will likely be unacceptably short, perhaps only several days.